Ralf Reussner Jens Happe Annegret Habel Modelling Parametric Contracts and the State Space of Composite Components by Graph Grammars. 80-95 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3442&spage=80 2005 conf/fase/2005 FASE db/conf/fase/fase2005.html#ReussnerHH05